492 research outputs found

    Ionization potentials and polarizabilities of superheavy elements from Db to Cn (ZZ=105 to 112)

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    Relativistic Hartree-Fock and random phase approximation methods for open shells are used to calculate ionization potentials and static scalar polarizabilities of eight superheavy elements with open 6d6d-shell, which include Db, Sg, Bh, Hs, Mt, Ds, Rg and Cn (ZZ=105 to 112). Inter-electron correlations are taken into account with the use of the semi-empirical polarization potential. Its parameters are chosen to fit the known ionization potentials of lighter atoms. Calculations for lighter atoms are also used to illustrate the accuracy of the approach.Comment: 5 papers, 4 tables, no figure

    Combination of the single-double coupled cluster and the configuration interaction methods; application to barium, lutetium and their ions

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    A version of the method of accurate calculations for few valence-electron atoms which combines linearized single-double coupled cluster method with the configuration interaction technique is presented. The use of the method is illustrated by calculations of the energy levels for Ba, Ba+^+, Lu, Lu+^+ and Lu2+^{2+}. Good agreement with experiment is demonstrated and comparison with previous version of the method (Safronova {\em et al}, PRA {\bf 80}, 012516 (2009)) is made.Comment: 7 pages, 5 tables, no figure

    Hyperfine-induced electric dipole contributions to the electric octupole and magnetic quadrupole atomic clock transitions

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    Hyperfine-induced electric dipole contributions may significantly increase probabilities of otherwise very weak electric octupole and magnetic quadrupole atomic clock transitions (e.g. transitions between ss and ff electron orbitals). These transitions can be used for exceptionally accurate atomic clocks, quantum information processing and search for dark matter. They are very sensitive to new physics beyond the Standard Model, such as temporal variation of the fine structure constant, the Lorentz invariance and Einstein equivalence principle violation. We formulate conditions under which the hyperfine-induced electric dipole contribution dominates. Due to the hyperfine quenching the electric octupole clock transition in 173^{173}Yb+^+ is two orders of magnitude stronger than that in currently used 171^{171}Yb+^+. Some enhancement is found in 143^{143}Nd13+^{13+}, 149^{149}Pm14+^{14+}, 147^{147}Sm14+^{14+}, and 147^{147}Sm15+^{15+} ions.Comment: 5 papers, 3 tables, no figure

    Current trends in searches for new physics using measurements of parity violation and electric dipole moments in atoms and molecules

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    We review current status of the study of parity and time invariance phenomena in atoms, nuclei and molecules. We focus on three most promising areas of research: (i) parity non-conservation in a chain of isotopes, (ii) search for nuclear anapole moments, and (iii) search for permanent electric dipole moments (EDM) of atoms and molecules which are caused by either, electron EDM or nuclear T,PT,P-odd moments such as nuclear EDM and nuclear Schiff moment.Comment: 6 pages; the article is based on invited talk at the Workshop on Fundamental Physics using atoms (FPUA2010), 7-9 August, 2010, Osaka, Japa

    Atomic optical clocks and search for variation of the fine structure constant

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    Theories unifying gravity and other interactions suggest the possibility of spatial and temporal variation of physical ``constants''. Accuracy achieved for the atomic optical frequency standards (optical clocks) approaches the level when possible time evolution of the fine structure constant α\alpha can be studied by comparisons of rates between clocks based on different atomic transitions in different atoms. The sensitivity to variation of α\alpha is due to relativistic corrections which are different in different atoms (Z2α2\sim Z^2\alpha^2). We have calculated the values of the relativistic energy shifts in In II, Tl II, Ba II and Ra II which all can be used as atomic optical clocks. The results are to be used to translate any change in the clock's rate into variation of α\alpha.Comment: 5 pages; LaTeX; Submitted to Phys. Rev.

    Calculation of parity non-conservation in xenon and mercury

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    We use configuration interaction technique to calculate parity non-conservation (PNC) in metastable Xe and Hg [proposal of the experiment in L. Bougas et al, Phys. Rev. Lett. 108, 210801 (2012)]. Both, nuclear spin-independent and nuclear spin-dependent (dominated by the nuclear anapole moment) parts of the amplitude are considered. The amplitudes are strongly enhanced by proximity of the states of opposite parity.Comment: 8 pages, 5 tables, no figure

    Parity nonconservation in hyperfine transitions

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    We use relativistic Hartree-Fock and correlation potential methods to calculate nuclear spin-dependent parity non-conserving amplitudes (dominated by the nuclear anapole moment) between hyperfine structure components of the ground state of odd isotopes of K, Rb, Cs, Ba+, Yb+, Tl, Fr, and Ra+. The results are to be used for interpretation of current and future measurements.Comment: 5 pages, 3 tables, no figure

    Theoretical study of the experimentally important states of dysprosium

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    Configuration interaction method is used to calculate transition amplitudes and other properties of the low states of dysprosium which are used in cooling and in study of the time variation of the fine structure constant and violation of fundamental symmetries. The branching ratio for the cooling state to decay to states other than ground state is found to be smaller than 10410^{-4}. The matrix element of the weak interaction between degenerate states at E=19797.96E=19797.96 cm1^{-1} is about 2 Hz which is consistent with the experimental limit HW=2.3±2.9(statistical)±0.7(systematic)|H_W| = |2.3 \pm 2.9({\rm statistical}) \pm 0.7({\rm systematic})| Hz [A. T. Nguyen, D. Budker, D. DeMille, and M. Zolotorev, Phys. Rev. A {\bf 56}, 3453 (1997)] and points to feasibility of its experimental measurement. Applications include search for physics beyond the standard model using the PNC isotopic chain approach.Comment: 5 pages, 5 tables, no figure

    Calculation of the (T,P)-odd Electric Dipole Moment of Thallium

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    Parity and time invariance violating electric dipole moment of 205^{205}Tl is calculated using the relativistic Hartree-Fock and configuration interaction methods and the many-body perturbation theory. Contributions from the interaction of the electron electric dipole moments with internal electric field and scalar-pseudoscalar electron-nucleon (T,P)-odd interaction are considered. The results are d(205Tl)=582(20)ded(^{205}{\rm Tl})=-582(20) d_e or d(205Tl)=7.0(2)×1018CSPecmd(^{205}{\rm Tl})=-7.0(2)\times 10^{-18}C^{SP} e {\rm cm}. Interpretation of the measurements are discussed. The results of similar calculations for 133^{133}Cs are d(133Cs)=124(4)ded(^{133}{\rm Cs})=124(4) d_e or d(133Cs)=0.76(2)×1018CSPecmd(^{133}{\rm Cs})=0.76(2)\times 10^{-18}C^{SP} e {\rm cm}.Comment: 5 pages, 4 tables, no figure

    Comment on "Reappraisal of the Electric Dipole Moment Enhancement Factor for Thallium"

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    Recent paper by Nataraj {\em et al} (Phys. Rev. Lett. {\bf 106}, 200403 (2011)) presents calculations of the EDM enhancement factor for Tl, which disagrees with previous most accurate calculations. The authors claim that their calculations of Tl EDM are the most accurate due to more complete treatment of higher-order correlations. In this note we argue that this claim is not supported by sufficient evidence. Nataraj {\em et al} also present misleading comments about our calculations. We explain our method and reply to the Nataraj {\em et al} comments.Comment: 2 pages, 1 figure, more discussion is adde